Succinic ester synthesis



Patented Dee. in, ma 2,457,111

STATES PATENT OFFICE 2,457,111 SUOCINIC ESTER SYNTHESIS reoham lnmn, Del, assiznor to E. I. du Pont de Nemours & Company. Wilminmn. M, a corporation oi Delaware No Drawing. an lieation March 28, 1947, sa-la? No. 738,007

7 Galina. (01. 260-485) a 2 the range of about 125 to 300 0., preferably about 190 to 220 C. under a pressure oi at least about 300 atmospheres. or higher, preferably about 500 to 1500 atmospheres, in the presence acid by reaction between carbon monoxide and a of a catalyst to be hereinafter described. It is esters oi beta-alkoxypropionic acids in accordfl-nce with the following equation: ROG H CO Rococ peratures, e. 3. below 125 0., to be avoided if high Hac OR +co monsoon the desired dialkyl succinates are to be wherein R and R are alkyl roups. pr f a obtained by reaction between carbon monoxide alkyl groups containing from 1 to 4 carbo "UNI TED talysts. One way of avoiding the decomposition of the beta-alkoxypropionic esters is to heat the mixture of beta-aikoxypropionic l -*1 nd pr ss r s n the Pre e of catalysts l5 ester. carbon monoxide and catalyst to a reaction temperature above about 125 very rapidly, e. g.

to yield methanol and methyl acrylate in accordcrnocrncmcmcm CH30H+CH2=CHCOOCH3 Moreover, at a temperature of about 100 to 105 s i s. or m h n flu id hydr n under a carbon monoxide pressure 01' about 800 irtually no dimethyl succin In general, the BF::, H2804, and H4P2o7 catalysts Another object of the invention is to provide a pared by admixing 85% phosphoric acid with a under the reaction conditions.

Optimum yields of dialkyl succinates are obtained in the practice of the invention by the use of anhydrous BF: as the catalyst. In order to ob- R', R and R being alkyl groups tain highest yields it is essential to control the preferably containing from 1 to 4 carbon atoms. initial mol ratio or BFxbeta-methoxypropiouic with carbon monoxide at a temperature within 55 ester so that it is within the range of about 0.8

invention will appear hereinafter. The objects of the invention are accomplished by heating a beta-alkoxy ester of the formula to 1.3. Other mol ratios of BFxbeta-alkoxyprouct was made basic with a solution sodium pionic ester may be employed but the yields are methylate in methanol and distilled, giving 18.8 considerably higher when the moi ratio is within grams of a mixture boiling from 30 to 70 at 1 mm.

the above-mentioned preferred range. The resulting product contained dimethyl suc- Any suitable method may be employed for the 5 cinate (ca. to conversion). recovery of dialkyl succinates from the reaction The dialkyl succinates obtai d as above product obtained in accordance with the present scribed can be converted to succinic acid by acid invention. For example, the acidic catalyst may hydrolysis. Moreover, they are widely useiul per be destroyed by reaction with sodium methyIB-te se and as intermediates in the manufacture of dissolved in methanol, and the dialkyl succinate 1o glycols, diamides, i itril s, and t li can thereafter be distilled without decomposition t, is t b d t d t t t above examples from the resulting mixture. When the BF: are illustrative only and t do not hm t catalyst is employed it y be removed from the invention in any way. Since many modifications reactio product by treatment with an alkali of the invention will occur to those who are skilled metal or alkaline earth metal fluoride, which 15 m th t, it, 1 t be d t d t t, 1 do t reacts therewith to form an alkali metal or allimit myself except as set forth in the following kaline earth metal fluoroborate. Any other conlai venient method for destroying or removing the 1 l i boron trifluoride c ta y m y be mp y 1. A process for the synthesis of esters of suc- The invention is illustrated further by means m; d h h comprises heating a b ta- .1kmof the following exa p propionic ester of the formula ROCHzCH'zCOOR', Ex mp beta-methmiyplopiobflte R and R being alkyl groups containing from 1 was charged into a shaker tube boron 1111- to 4 carbon atoms carbon monoxide at a fluoride, and carbon monoxide was injected under temperature within the range of to m Q in high Pressure- The reaction conditions and the presence of a catalyst of the-class consisting version to dimethyi succinate, are set forth in of EFL H2304, and

114F201, under a pressure of the following tables at least about 300 atmospheres whereby a dialkyl succinate of the formula ROCOCHzCI-IzCOOR' is produced, and recovering the said dialkyl succinate from the resultant reaction mixture.

2. A process for the synthesis of esters of succinic acid which comprises heating the methyl Effect of BF::Methyl-beta-methoxypropionate ratio in shaker tube experiments leading to dimethyl succinote Conversion Tempcraq C0 BFWISW m1 mmowl ester of beta-methoxypropionic acid with carbon turc 0 sure (otmJ ratio bummw monoxide at a temperature within the range or f about 125 to 300 C. in the presence of a catalyst .3 A 5o mm M1 of the class consisting of BFs. H2501 and 114F201, gin-gig so :12:13 al under a pressure within the range of about 500 -2 1 hit-sin ilus m to 1500 atmospheres, and recovering dimethyl 210-240 .40 5-"r800 l. 51 ca. 15

40 succinate from the resultant reaction product.

3. A process for the synthesis of esters of suc- Efiect of temperature on the synthesis of dimethyl succinate from carbon monoxide, me thyl-betdmethomypropionate,

and BF 3 R 'icmperu- Time CD nrcs- BFz: csicr Conversion to Dina ture sure (atm.) rat in methyl Suocinatc C. Min. 201 100-105 30 800-790 1. 5 0 (methyl acryiatc was iormed). 2b 200 30 405-800 1. D8 2c 237-255 20 580-800 1. 1 LOW.

Example 2.-A charge consisting of 98 grams cinic acid which comprises heating the methyl of concentrated sulfuric acid and 118 grams Oi ester of beta-methoxypropionic acid with carbon methyl beta-methoxypropionate monoxide at a temperature within the range oi 011306EhcrhcoQCH3 about 190 to 220 C. in the presence of a catalyst of the class consisting of BFa, H2804 and HiPzO'l, was P Q in 325 snver-uned Shaker under a pressure within the range of about 500 tube at 250 to 272 C. for 1 o at 640 to 1500 atmospheres, and recovering dimethyl sucto 800 atmospheres pressure of carbon monoxide. 60 emote fr m resultant reaction product.

e p e e d p a 230 atmosp The 4. A process for the synthesis of esters of sucdischarged liqu d wa made basic with sodium cinic acid which comprises heating the methyl met y fl fl in methanol distilled- After the ester of beta-methoxypropionic acid with carbon removal of methanol, there was obtained 15.1 monoxide to a temperature within the range f a of liquid boiling in the range methyl 125 to 300 0. in the presence of boron trifluoride,

succinate. This corresponds to a conversion of the said heating being sumdemly mm d so that fg' g based on methyl beta-methoxypmpio' the reaction mixture is at a temperature between 1 charge consisting of 702 grams room temperature and 125 C. for a period of time at orthophosphoflc and 415 grams phos 70 not in excess of 20 minutes, thereafter continuphoric anhydride (corresponding to M the heating at a temperature the range HiPzO-z) and 114 grams of methyl betam of to 300 C. whereby dimethyl succinate is ypropionate'was processed in a silver-lined shaker P u and thereafter separatin t e S id ditube at 275 to 280 for 1 hour at 595 to "(00 atmethyl succinate from the resulting reaction mixmospheres carbon monoxide pressure. The prod- 16 ture.

5. A process for the synthesis of esters or succinlc acid which comprises heating a mixture consisting of earbon monoxide and the methyl ester oi beta-methoxyprcpionic acid to a temperature of about ijfl' to 300 0.. introducing an acid catalyst of the class consisting oi BFa, H604, and M20: into the said mixture at the said temperature. maintaining the resulting mixture at a temperature 01' about 125 to 800 C. until a substantial quantity of dimethyl succinate is formed, and thereafter separating the said dimethyl succinate from the resulting reaction mixture.

d. A process for the synthesis or esters oi succinic acid'iwhich comprises heating a mixture consistlng otzcarbon monoxide and the methyl ester 01' bets-methoxypropionic acid to a temperature or about 185 to 800 0.. introducing an acid catalyst oi the class consisting of BIB, M04. and am iii to the said mixture at the said temperaturegmaintaining the resulting mixture at a temperature of about 190 to 220 C. until a substantial quantity of dimethyl succinate is formed. and thereaiter separating the said dimethyl succinate from the resulting reaction mixture.

7. A process for the synthesis oi dimethyi succinate which comprises heating a mixture consisting essentially of carbon monoxide, BBB, and the methyl ester or beta-methoxypropionlc acid, the moi ratio of BFszmethyi ester of beta-methoxypropionic acid being initially from 0.8 to 1.3, at a temperature within the range of 125 to 800 0. without subjecting the said mixture to a temperature of about 50 to 125 for any period of time in excess or about 10 minutes, continuing the, said heating at 125 to 300 C. until a substantial quantity oi dimethyi succinate is formed, and thereafter separating the said dimethyl succinate from the resulting reaction mixture.

WILLIAM F. GRESHAM.

REFERENCES CITED The following references are of record in the file of this patent:

2,130,450 Larson Nov. 1. 193a 

